Table of Contents
Introduction to Python catch multiple exceptions
In Python, try-except blocks are used to catch exceptions and process them. Sometimes we call a function that may throw multiple types of exceptions depending on the arguments, processing logic, etc. In this tutorial, we will learn about Python catching multiple exceptions. We will discuss how we can handle multiple exceptions that might occur during the execution of our Python program through various methods.
We will also learn how we can use multiple except blocks, python loop, and user-defined exceptions to handle multiple exceptions. At the same time, we will also learn how we can handle multiple exceptions just in one line using tuples by taking various examples. Moreover, we will also discuss how we can handle different types of exceptions by solving different examples. In a nutshell, this tutorial will contain all the necessary methods that you can use in order to handle multiple exceptions in the Python programming language.
Getting Started with Python catch multiple exceptions
As we have already discussed that try-except blocks in Python are used to handle different types of exceptions. You can learn more about the try and except block from the article on Python try and catch exceptions. In this section, our main focus will be to handle multiple exceptions using try and except blocks. The following is the simple syntax of the try and except block.
try:
# statements inside try block
except:
# statements inside except blockIf an error occurs, in the try block then rather than terminating the program, the except block will be executed.
Method-1 Python catch multiple exceptions using python for loop
Python for loop is used to loop through an iterable object (like a list, tuple, set, etc.) and perform the same action for each entry. We can use handle multiple exceptions that might occur while iterating an object. In such a case, we can use the try and catch block inside our Python for loop which will handle multiple exceptions. The following is the simple syntax.
for i in iterable:
try:
# try block statements
except:
# raise an erroNotice that we have handled exceptions that might occur inside for loop.
Example of Python catch multiple exceptions using for loop
Now let us take an example and see how we can use the python for loop to catch multiple exceptions. See the example below:
# iterable object
mylist = [-1, 2, 0, 4, 0]
# for loop
for i in mylist:
# Python catch multiple exceptions
try:
# raise when divide by zero
print("thedivision is:", 10/i)
# this block will be executed if error occurs
except:
# raise an error
print("Error occurs while dividing")Output:
the division is: -10.0
the division is: 5.0
Error occurs while dividing
the division is: 2.5
Error occurs while dividing
Notice that the above program had raised two errors but was handled successfully using the except block.
Method-2 Python catch different types of Exceptions
In python, there are many built-in exceptions for example ZeroDivisionError, IndexOutOfRange, TypeError, and many more. ZeroDivisionError occurs when a number is divided by zero and TypeError occurs when different data types are added or performed operations that cannot be performed. While IndexOutOfRange as the name suggests raises when the index is out of range. In this section, we will handle the given three types of errors. The following will be the simple syntax of handling the above different types of exceptions.
try:
# try block statement
except ZeroDivisionError:
# Raise exception
except IndexError:
# raise exception
except TypeError:
# raise exceptionDepending on the type of exception that occurs in the try block, that specific except block will be executed to handle the exception.
Example of Python catch different types of exceptions
Now let us see how we handle different types of exceptions that might occur during the execution of the try block. See the following Python program.
# Python catch multiple exceptions
try:
# defining variables
a = 10
b= 0
c = "abc"
# adding the variables
d =a+c
# Zerodivision error
except ZeroDivisionError:
# printing error
print("Zero Division Error occurs")
# index error
except IndexError:
# printing
print("Index error occurs")
# type error
except TypeError:
# printing
print("Type error occurs")Output:
Type error occurs
Type error occurs because in Python we cannot directly add string and integer data types together. So because the type error was thrown by the try block, that is why only the TypeError except block was executed.
Method-3 Python catch multiple exceptions in one line
Instead of writing different types of exceptions in different except blocks, we can write them in one line using a tuple. A Tuple is nothing, just a collection of Python objects separated by commas. We write all the exception types that might occur in a tuple and use one except block. See the following syntax of multiple exceptions in one line.
try:
# Try statements
except(TypeError, SyntaxError, ValueError, ...)as e:
# exceptionsNotice that we have condensed all the exceptions in just one line using by writing then inside a typle.
Example-1 Python catch multiple exceptions in one line
Now let us see how we can handle multiple exceptions in just one line. See the python program below:
# Python catch multiple exceptions
try:
# defining variables
a = 10
b = 0
c = 'sd'
# adding
d = a+c
# except block
except(TypeError, SyntaxError, ValueError)as e:
# printing the error
print("The following error occurs:")
print(e)Output:
The following error occurs:
unsupported operand type(s) for +: 'int' and 'str'
Notice that the type error occurs and was handled in the except block.
Example-2 Python catch multiple exceptions in one line
Now let us try to divide the number by zero and run our program.
# Python catch multiple exceptions
try:
# defining variables
a = 10
b = 0
c = 'sd'
#dividing
d = a/b
# except block
except(TypeError, ZeroDivisionError, ValueError)as e:
# printing the error
print("The following error occurs:")
print(e)Output:
The following error occurs:
division by zero
Notice that this error was also handled by the except block because ZeroDivisionError was mentioned in the tuple.
Method-4 Python catch all exceptions
Sometimes, we might don't know what kind of exception might occur. In such a scenario, it is better to handle all exceptions that might occur without specifying the type of error. The following is the simple syntax to handle all exceptions.
try:
# Try block and statements
except Exception:
# handle exceptionsNotice that here we did not have defined any type of exceptions, we have used the keyword exception which covers all types of exceptions that might occur during the execution of our program.
Example-1 Python catch all exceptions
Now let us see how the exception keyword works and handle all possible exceptions that might occur during the execution of our program. See the python program below:
# Python catch multiple exceptions
try:
# defining variables
a = 10
b = 0
c = 'sd'
#dividing
d = a/b
# except block
except Exception as e:
# printing the error
print("The following error occurs:")
print(e)Output:
The following error occurs:
division by zero
Notice that the exception part handled the zero exception and printed the error.
Example-2 Python catch all exceptions
Now let us try to come up with another exception. See the python program below:
# Python catch multiple exceptions
try:
# defining variables
a = 10
b = 0
c = 'sd'
#adding
d = a + c
# except block
except Exception as e:
# printing the error
print("The following error occurs:")
print(e)Output:
The following error occurs:
unsupported operand type(s) for +: 'int' and 'str
Notice the exception part handled another exception as well. This block will be able to handle all the built-in exceptions that might occur during the execution of the python program.
Method-5 Python catch user-defined exceptions
Sometimes, we might need to handle exceptions other than the built-in ones. In such a case, we have to define an exception on our own and then handle it, if it occurs. The following is the simple syntax of python's user-defined exception.
try:
# if statement
if conditions:
# raise error
raise Error1
elif conditions:
raise Error2
except Error1:
# handle error 1
except Error2:
# handle error 2Notice that we have used if and else statements to define a user exception and then handle it in the except block.
Example of Python catch user-defined exception
Now let us see how we can catch a user-defined exception. See the following Python program.
# defining class
class Number(Exception):
pass
# creating new class for small number error
class SmallNumberError(Number):
pass
# Python catch multiple exceptions
try:
# defining variables
a= 10
b=-1
# condition for exceptions
if b< 0:
# raise an exception
raise SmallNumberError
else:
print("No error")
# except block to handle exception
except SmallNumberError:
print("The number is too small:")Output:
The number is too small:
Notice that we have defined an exception on our own that if a number is smaller than 0 then raise an exception and we handle it in the except block.
Summary
In Python, we use the try and except blocks to catch and handle any kind of exceptions and errors that might occur during the execution of our program. In this tutorial, we have learned about python catch multiple exceptions by using various methods. We have discussed five different ways of handling multiple exceptions by taking various examples. We covered how we can handle exceptions using except blocks, different types of exceptions and how we can handle all types of exceptions in just one line. Moreover, we also discussed how we can define our own exception and handle it. To summarize, this tutorial contains all the necessary methods that are used to handle multiple exceptions in different scenarios
Further Reading
Python try and except
Python exception handling
Python built-in Exceptions
